(a) Field of the Invention
The present invention relates to an automatic gain control method in a wireless packet communication system.
(b) Description of the Related Art
A wireless communication system receives a signal, and demodulates the signal by amplifying it. The received signal may be deviated from a dynamic range of an analog-digital converter if a gain is too great when the received signal is amplified in the wireless communication system. Accordingly, a demodulator does not appropriately demodulate the received signal due to distortion of a digital signal. When the gain is too small, demodulation performance is reduced since a quantization noise affects the wireless communication system. Accordingly, it is important to successfully perform the automatic gain control because performance of the entire system is determined according to success or failure of the automatic gain control. Specifically, in wireless packet communication, the automatic gain control is required to be performed in an initial preamble period, and a packet error occurs when the automatic gain control fails. Therefore, the performance of the system is directly affected by the success or failure of the automatic gain control.
In a conventional automatic gain control method, a link is formed between a transmitter and a receiver in a like manner of a cellular system, and the gain is sequentially tracked when the automatic gain control is continuously performed by a pilot channel. In the method, a received power is measured while a signal power is established, and a difference between the signal power and the received power is gradually reduced. While the conventional automatic gain control method has high performance for keeping up with variations of a channel gain and controlling the gain, an initial convergence time may be too long to apply the method to a packet communication system.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention, and therefore, unless explicitly described to the contrary, it should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.